A cutting edge tip of a cubic boron nitride sintered body has improved joint strength to a substrate of a cemented carbide. A cutting edge tip of a cubic boron nitride sintered body has improved crater wear resistance. A tool 10 of the present invention includes a substrate 12 of a cemented carbide and a cutting edge tip 14 of a cubic boron nitride sintered body joined to the substrate 12. The cutting edge tip 14 has a thickness covering an upper surface 12a to a lower surface 12b of the substrate 12. The cubic boron nitride sintered body contains 50 volume % or more and 95 volume % or less of cubic boron nitride and 5 volume % or more and 50 volume % or less of a binder phase. The cubic boron nitride has an average grain size of 1.0 m or more and 6.0 m or less.

The present disclosure reduces equipment failures, decreases maintenance frequency, and stabilizes cutting operation. Specifically, a holder (5) includes a fitting surface (52) capable of fitting a distal end (2a) of an electrode tip (2). A cutting member (6) having a cutting blade (6b) is attached to the holder (5) and the cutting blade (6b) cuts the distal end (2a) of the electrode tip (2) by rotating the holder (5). On the fitting surface (52), a plurality of grooves (52a) extending arcuately around the rotation axis (C1) as the center thereof are consecutively formed adjacent to each other toward the rotation axis (C1).

A coated tool disclosure includes a base body and a coating layer. The coating layer includes crystals having a cubic structure. The coating layer has a striped structure in cross-sectional observation by a transmission electron microscope. The striped structure has two layers alternately located in a thickness direction. The two layers contain Si and at least one metal element. The two layers each contain crystals having the cubic structure. When a lattice constant of a crystal having the cubic structure in one layer of the two layers is referred to as a first lattice constant and a lattice constant of a crystal having a cubic structure in the other layer of the two layers is referred to as a second lattice constant, a difference between a magnitude of the first lattice constant and a magnitude of the second lattice constant is greater than 0% and 0.1% or less.

A surface-coated titanium carbonitride-based cermet cutting tool is a surface-coated TiCN-based cermet cutting tool in which a Ti compound layer that is a hard coating layer is deposited as a first layer on the surface of a TiCN-based cermet body containing W and Mo, and a Mo-enriched layer having an average thickness of 0.5 to 10 nm is formed at an interface between a TiCN phase of the body and the hard coating layer.

A surface-coated cutting tool includes a base material and a coating formed on the base material. The coating includes an -Al.sub.2O.sub.3 layer. The -Al.sub.2O.sub.3 layer contains -Al.sub.2O.sub.3 crystal grains and sulfur, and has a TC(006) of more than 5 in texture coefficient TC(hkl). The sulfur has a concentration distribution in which a concentration of the sulfur decreases in a direction away from a base-material-side surface of the -Al.sub.2O.sub.3 layer, in a thickness direction of the -Al.sub.2O.sub.3 layer.

A coated cutting tool for chip forming machining of metals includes a substrate having a surface coated with a chemical vapour deposition (CVD) coating. The coating has a layer of -Al.sub.2O.sub.3, wherein the -Al.sub.2O.sub.3 layer exhibits a texture coefficient TC(0 0 12)7.2 and wherein the ratio of I(0 0 12)/I(0 1 14) is 1.

In an embodiment, a cutting insert includes an upper surface, a one or more side surfaces, and a cutting edge. The upper surface includes a first corner portion, and a first side that is adjacent to the first corner portion. The one or more side surfaces are adjacent to the upper surface. The cutting edge is disposed on at least a portion of a section where the upper surface and the side surfaces intersect. When viewed from directly above, the cutting edge includes first, second, third and fourth cutting edges. The first cutting edge is disposed at the first corner portion and has a convex curved shape. The second cutting edge is next to the first cutting edge, and has a linear shape. The third cutting edge is next to the second cutting edge, and has a convex curved shape. The fourth cutting edge is next to the third cutting edge on the first side.

A coated cutting tool includes a substrate having a rake side, a clearance side and a cutting edge and a coating comprising a first layer and a second layer. The second layer has a sandwich structure of an inner layer, an intermediate layer and an outer layer, wherein the inner layer is exposed through an opening in the outer layer, the opening extending over at least a portion of the width of the cutting edge. Thereby, a double layer is provided in critical areas, whereas a single layer is provided in other areas. The double oxide layer is an aluminum oxide layer. A method for manufacturing the coated cutting tool is also provided.

A coated tool includes a base and a coating layer located on the base. The coating layer includes a first layer having a thickness of 1 m or more located near the base, and a second layer located more away from the base than the first layer. An erosion rate A2 in the second layer is 0.4 m/g or less which is obtained from a measurement by collision of a liquid A, in which 3 mass % of spherical Al.sub.2O.sub.3 particles having a mean particle diameter of 1.1-1.3 m is dispersed in pure water, against the second layer. An erosion rate A1 in the first layer is 1.8 m/g or less which is obtained from a measurement by collision of the liquid A against the first layer. A cutting tool includes a holder which includes a pocket, and the coated tool located in the pocket.

In one aspect, a coated cutting tool described herein comprises a substrate and a coating adhered to the substrate, the coating including a refractory layer comprising AlON, the AlON layer exhibiting a peak in a range of 33-35 2 in an XRD, wherein the peak has a FWHM of 0.1-0.7 2. In some embodiments, the AlON layer can exhibit a ribbon-like crystallites, needle-like crystallites, or rice-like crystallites and associated surface texture.